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POHow to copy generically superclass instances to subclass instances?
 

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  1. POHow to copy generically superclass instances to subclass instances?
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    <p>I have a class hierarchy / inheritance like this:</p> <pre><code>public class A { private String name; // with getters &amp; setters public void doAWithName(){ ... } } public class B extends A { public void doBWithName(){ // a differnt implementation to what I do in class A } } public class C extends B { public void doCWithName(){ // a differnt implementation to what I do in class A and B } } </code></pre> <p>So at one time there is a instance of class A with the initialized field "name". Later I want this instance of A get wrapped into instance of B or C. So the superclasses should be get wrapped with a subclass!</p> <p>How can I make this most efficent with respect to DRY?<br> I've thought about a constructor that does some copying with the getters/setters. But in this case I have to repeat myself - and this doesn't respect anymore to my initial requirement of DRY! </p> <p>So, how can I warp A to B by just initializing B's new fields (with default values) and delegating the rest to a method in A (which knows more than B about which fields of A should be accessed...). </p> <p>In the same way:<br> If A should be wrapped into C only a method in c should init C's 'new' fields, delegate to B's wrap method (which therefore inits B's 'new' fields in C) and at last B delegates to A which copies it's fields to the fields of C).</p> <p>So in the end I have a new instance of C which has the values of A wrapped (and some default init values to the fields which the inheritance hierarchy has added).</p>
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